The present invention relates to optical fibers. More particularly, it relates to a method for determining the light energy transmission characteristics and efficiencies of coupled optical fibers.
In coupling fibers to one another and to various types of optical components to form optical fiber networks, it is often times desirable to measure the light transmission efficiency or other transfer characteristics of a particular optical path, coupling, or component. While it is a relatively straight forward matter to measure light energy transmission through an in-line optical fiber, coupling, or component, the problem is made more difficult when attempting to measure coupling efficiencies in a network where the light energy present at any one exit port can represent light from several different optical paths in the network. For example, it is difficult to measure the transfer characteristics of a single optical fiber that is looped upon and laterally coupled to itself to form an in-line resonant loop. The light at the exit port represents both light transmitted through the lateral coupling and through the resonant loop.
The need for reliable methods for determining light energy transfer efficiencies is particularly important in multi-channel, wavelength multiplexed communications systems where a large number of wavelength unique information-bearing signals are present on a primary trunk line and where signals of one or more wavelengths are removed using wavelength tuned optical components. Accordingly, a need exists for measuring light energy transfer characteristics in various types of networks which method is reliable and can be accomplished with minimum disruption of the network operation.